Field of the Invention
The present invention relates to construction materials for creating monolithic biocomposite walls or ceilings, as well as processes for preparing and using such materials, and, more particularly, to a prefabricated shuttering panel for creating cast-in-place mass walls.
Description of the Related Art
Production of walls using bioaggregates formed from dried and processed cellulose fibers and binder, such as hemp and lime, hemp-lime or hemperete, is a well-known construction technique. Use of such bioaggregates is often desirable due to the natural, non-toxic composition, thermal performance, hygrometric regulation, phonic qualities, and fire and pest resistance of the bioaggregate materials.
A traditional method for casting a biocompatible wall, referred to as slip-forming, involves preparing a wet mineralized cellulose (e.g., hemperete) mixture in situ and filling two opposing formworks or shutterings attached directly to, or offset from, a framing of the structure being built. This slip-forming method of filling or pouring between formworks requires tamping down the bioaggregate at the facing surface of the formwork to increase the material density of the wall structure, which enhances the integrity of the wall. In some cases, it is desirable to leave the central portion or mass of the wall in a less dense state for greater insulating value. The formwork is removed once the bioaggregate has set into a hardened state. The time for setting the bioaggregate is usually 24 to 48 hours, to allow the binder in the wall to partially activate, allowing the bioaggregate to substantially harden. After the formwork is removed, drying and curing the hemperete can take many weeks or months. The final product created from this process is a monolithic biocomposite wall material surrounding the structural building framing.
This traditional slip-forming process is slow due to installing and removing the temporary formwork, requires special considerations while framing, and creates long time delays in order to have the bioaggregate material dry out enough to allow final finishing work to begin on the interior and exterior wall surfaces. It is also time-consuming and difficult to produce a wall with a variety and/or gradient of material densities between the surface and interior mass of a wall. However, as previously discussed, a wall with a dense surface and less dense internal mass is desirable to enhance both integrity and thermal resistance of the structure.
To solve some of these material drawbacks, other construction products incorporate bioaggregates, like hemperete, into various forms including prefabricated bricks, blocks, structural blocks, and completely custom structurally insulated panels (SIP). All of these products are single-density biocomposites.
An improved and more universal factory-produced biocomposite product and wall building system adapted for use with current wood-framing construction methods is needed. Such a factory-produced biocomposite wall would allow for a larger range of building possibilities, while reducing the time required for assembly and drying. The panels, walls, and wall systems disclosed herein are intended to address these challenges.